All of lore.kernel.org
 help / color / mirror / Atom feed
From: Lennart Poettering <lennart@poettering.net>
To: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@fb.com>,
	Ming Lei <ming.lei@redhat.com>, Martijn Coenen <maco@android.com>
Cc: linux-block@vger.kernel.org, Luca Boccassi <bluca@debian.org>,
	Karel Zak <kzak@redhat.com>
Subject: Is LO_FLAGS_DIRECT_IO by default a good idea?
Date: Mon, 18 Oct 2021 16:19:20 +0200	[thread overview]
Message-ID: <YW2CaJHYbw244l+V@gardel-login> (raw)

eMing, Christoph, Jens!

Ming, 5 years ago or so you added support for dio/aio for the
loopback block device, i.e. LO_FLAGS_DIRECT_IO. As I understood it's
supposed to improve performance of loopback block devices
substantially. I noticed that there's various software that enables it
by default (Android, Docker), but a lot of other candidates currently
do not (util-linux, Ubuntu Snaps, various systemd tools). We recently
got a request to enable it by default in systemd, but information is
scarce on the precise effect of enabling this, and whether there are
any drawbacks.

So my question really is just: is this a flag we should all just
enable by default? Is there any reason not to enable it? Should
util-linux' losetup defaults be changed regarding this?

A brief answer like "yes, please, enable by default" would already
make me happy.

Thank you,

Lennart

--
Lennart Poettering, Berlin

             reply	other threads:[~2021-10-18 14:25 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-18 14:19 Lennart Poettering [this message]
2021-10-18 15:05 ` Is LO_FLAGS_DIRECT_IO by default a good idea? Christoph Hellwig
2021-10-19  7:28   ` Lennart Poettering
2021-10-19  7:44   ` Ming Lei
2021-10-19 12:24     ` Jens Axboe
2021-10-25 10:37       ` Karel Zak

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=YW2CaJHYbw244l+V@gardel-login \
    --to=lennart@poettering.net \
    --cc=axboe@fb.com \
    --cc=bluca@debian.org \
    --cc=hch@lst.de \
    --cc=kzak@redhat.com \
    --cc=linux-block@vger.kernel.org \
    --cc=maco@android.com \
    --cc=ming.lei@redhat.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.